1. Field of the Invention
This invention relates to a wire-dot printer, and more particularly, to a printing head of such a printer including actuating devices for driving dot-impact wires or rods comprising, for example, electro or magnetic-distortion devices. This invention also relates to an electro-distortion device advantageously used for such a printing head of the wire-dot printer.
2. Description of the Related Art
Recently, high-speed wire-dot printing heads have become more widely used, and accordingly, to drive dot-impact wires or rods of such a high-speed printing head, actuators comprising electro or magnetic-distortion devices have been developed and used instead of electromagnet type drive elements.
For example, page 92 of "NIKKEI (Japan Economic) MECHANICAL" issued on Mar. 12, 1984, suggests that a printing head including such electro-distortion devices can be used. This electro-distortion device is made by the steps of: preparing a plurality of green sheets made of piezo-electric ceramics, forming a metal paste film on one of the surfaces of each of the green sheets to form an inner electrode, and laminating and sintering the plurality of green sheets.
To make a printing head using such an actuating device, a means for effectively enlarging the very small displacements of such an actuating element is required when driving the dot-impact wires or rods.